Affordability, reach, inequality score

Introduction

The reviews and decision models estimated the cost-effectiveness criteria. Three of the remaining criteria (affordability, reach, and inequality score) required evidence on two further parameters:

The proportion of the population who are eligible for the intervention.

The proportion of the population who were disadvantaged and eligible for the intervention.

These parameters were employed to measure the criteria in the following way:

Reach: The proportion of the population who are eligible for the intervention.

Inequality score: The ratio of the proportion of the population who were disadvantaged and eligible for the intervention and the proportion of the whole population who are eligible for the intervention.

Affordability: The proportion of the population who are eligible for the intervention was combined with estimate of the size of the population to arrive at a total number of people who could receive the intervention. This was then combined with the estimate of the unit cost of the intervention used in the decision modelling to calculate the budget required to deliver the intervention.

Data sources

The following sources were searched for data:

Office of National Statistics (ONS)

Departmental and associated organisations

Relevant charities

Google.co.uk

The data identified was reviewed for its relevance in measuring the evaluation criteria.

Reach

A hierarchy of evidence types was identified with which to estimate this criterion. Specifically, data that directly measured the criterion were preferred to multiple data that could be combined to measure the criterion. For example, when calculating the number of older people who are depressed and are likely to visit a GP, the ideal dataset would measure this directly. However, this estimate could also be produced by combining the following data:

The proportion of the population who are aged 65+.

The proportion of those aged 65+ who are depressed.

The proportion of older people with depression who visit the GP.

The reach criterion was calculated at a national level in the first instance. Sources of data are stated in Table 1.

The reach criterion was also calculated at PCT level where possible. However, only a small number of the 17 interventions had PCT level data on the number that could benefit from the intervention available. These were:

all interventions targeting obesity

the intervention targeting depressed older people

the school based intervention for increasing rates of condom use and reducing STI transmission and teenage pregnancy rates

For all other interventions, national ‘reach’ figures were used at PCT level.

Inequality Score

The inequality score criterion required an estimate of the proportion of the most disadvantaged 20% of the population who were eligible for the intervention. Due to lack of data, it was not possible to use a consistent definition of disadvantage across different health / behavioural states. The definitions of disadvantage employed are summarised in Table 2. If data on the proportion of disadvantaged people that exhibit a health state/behaviour was not available, it was assumed that the reach was the same as in the general population.

As there is no local data on the prevalence of health states/behaviour in disadvantaged populations, it is not possible to produce this figure at a PCT level. Consequently, all calculations used national level data.

Affordability

The affordability criterion combined estimates of the proportion eligible for the intervention and its unit cost. The resulting national-level affordability estimates were grouped into one of the following three categories:

>£1bn

£100m-£1bn

<£100m

Results

The results of the criteria calculation are reported in Tables 1 and 2.

Smoking: National mass media campaigns for reducing population smoking rates

Adult smokers

22.30%

General Household Survey (2007)

***

Smoking: Nicotine replacement therapy to improve quit rates

Adult smokers who would like to quit

12.82%

Healthcare Commission (2008), General Household Survey (2007)

***

Smoking: Increases in taxation to reduce population smoking rates

Adult smokers

22.30%

General Household Survey (2007)

***

STI / teenage pregnancy: Screening and treatment for reducing the prevalence of Chlamydia

Sexually active women aged 16-49

11.33%

ONS mid-2008 population estimates Contraception and sexual health, 2004/05 Series OS no.28. Assumes all women aged 16-49 using surgical contraception have one long term partner and are not at risk of contracting STIs.

**

STI / teenage pregnancy: School based group education for increasing rates of condom use and reducing STIs and unwanted pregnancy

Sexually active 11 to 16 year olds

0.52%

Proportion of sexually active under 16s from NATSEL (2000) Calculation assumes 50:50 M:F and have same chance of being sexually active.

Also assumes that all 16 year olds and half of 15 year olds are sexually active and all others in 11-16 age band are not.

Definition of terms used in Table 1

Where ONS quinary age groups population estimates did not match the age groups specified in the analysis, it was assumed that there are an equal numbers of individuals in each age in the band.

Attending a GP

Interventions delivered in a primary care setting were assumed to be available to people that had visited a GP in the last 12 months for any reason. The rate of GP attendance was available at PCT level and National level from the Local Health Services Survey.

Heavy Drinkers

>=40 g/day male, >=20g/day female.

Obese

BMI>30 kg/m2.

Older People

The definition of older people used was aged 65-74 unless otherwise stated.

References

LJMU (2008), Alcohol-attributable fractions for England - Alcohol-attributable mortality admissions. Commissioned by DH, produced by Centre for Public Health, Faculty of Health and Applied Social Sciences, Liverpool John Moores University